System and method for tire leak detection

ABSTRACT

A method for detecting a leak in a pressure vessel of a system including a plurality of pressure vessels in fluid communication with a common header comprises: reducing a fluid pressure in the common header to a first predetermined value below an operating pressure of the plurality of pressure vessels; gradually adding fluid to the common header at a first flow rate to increase the fluid pressure in the common header from the first predetermined value; monitoring, after gradually adding the fluid to the common header, the fluid pressure in the common header; and determining, based on the fluid pressure in the common header after gradually adding the fluid to the common header, a leak in at least one pressure vessel of the plurality of pressure vessels.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.16/745,084 filed Jan. 16, 2020 which is a continuation of U.S.application Ser. No. 16/398,596, filed Apr. 30, 2019 and granted as U.S.Pat. No. 10,688,836, which is a continuation of U.S. Nonprovisionalapplication Ser. No. 15/805,015, filed Nov. 6, 2017, and granted as U.S.Pat. No. 10,315,469, which claims the benefit of US ProvisionalApplication numbers 62/383,919, filed Sep. 6, 2016 and 62/384,652, filedSep. 7, 2016, all of which are incorporated in their entireties by thisreference.

FIELD

The present disclosure relates generally to managing fluid pressures andto detecting leaks in a pressurized fluid system.

BACKGROUND

A problem with conventional central tire inflation systems can arise ifone or more of the tires has a leak, and air can flow from the other,non-leaking tires, pressurizing the system, and thereby masking theleak. This can occur with both normally-open and normally-closedwheel-end check valves (WECVs).

SUMMARY

The present disclosure provides a method for detecting a leak in apressure vessel of a system including a plurality of pressure vessels influid communication with a common header. The method comprises: reducinga fluid pressure in the common header to a first predetermined valuebelow an operating pressure of the plurality of pressure vessels;gradually adding fluid to the common header at a first flow rate toincrease the fluid pressure in the common header from the firstpredetermined value; monitoring, after gradually adding the fluid to thecommon header, the fluid pressure in the common header; and determining,based on the fluid pressure in the common header after gradually addingthe fluid to the common header, a leak in at least one pressure vesselof the plurality of pressure vessels.

The present disclosure also provides a system for managing pressure in aplurality of tires of a vehicle. The system comprises: a manifolddefining a channel and configured to distribute compressed air from acompressed air source; a common header providing fluid communicationbetween the manifold and each of the plurality of tires; a control valveconfigured to control air flow from the compressed air source to thecommon header; a pressure sensor configured to monitor a pressure in thecommon header; and an electronic control unit in functionalcommunication with the control valve and the pressure sensor. Theelectronic control unit is configured to: reduce a fluid pressure in thecommon header to a first predetermined value below an operating pressureof the plurality of tires; gradually add air to the common header toincrease the fluid pressure in the common header from the firstpredetermined value; monitor, after gradually adding the fluid to thecommon header, the fluid pressure in the common header; and determine,based on the fluid pressure in the common header after gradually addingthe air to the common header, a leak in at least one of the plurality oftires.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details, features and advantages of designs of the inventionresult from the following description of embodiment examples inreference to the associated drawings.

FIG. 1 shows a schematic representation of an embodiment of a tiremanagement system.

FIG. 2 shows a flowchart diagram illustrating steps in a method formanaging pressure in a tire.

FIGS. 3A-3D show schematic diagrams of the tire management systemintegrated with a manifold of a vehicle.

FIG. 4 shows an arrangement of control valves within a manifold of avehicle.

FIGS. 5A and 5B show illustrations of air flow in a vehicle during tiredeflation and inflation, respectively.

FIG. 6 shows an example embodiment of a check valve.

FIGS. 7A-7D show the check valve in various configurations depending onthe operation of a control valve.

FIG. 8 shows a mounting mechanism retrofittably installed on a hubcap.

FIG. 9 shows a mounting mechanism.

FIG. 10 shows the mounting mechanism attached to a vehicle axle assemblywith a barbed press-in interface.

FIG. 11 shows a rotary union.

FIGS. 12A-12B show a rotary union allowing for misalignment between theaxle and the hubcap of a vehicle.

FIG. 13 shows a block diagram illustrating communication between thesystem and a remote entity.

FIG. 14 shows a block diagram of a tire pressure control system.

FIG. 15 shows the tire pressure control system of FIG. 14, with a slowleak in one of the tires.

FIG. 16 shows a graph illustrating pressures when checking a tirepressure in a system with inflate and deflate control capabilities.

FIG. 17 shows a graph illustrating pressures when checking a tirepressure in a system with only inflate control capability.

FIG. 18 shows a flow chart illustrating steps in a method forcontrolling tire pressure in a system with inflate and deflate controlcapabilities.

FIG. 19 shows a flow chart illustrating steps in a method forcontrolling tire pressure in a system with only inflate controlcapability.

FIG. 20 shows a flow chart illustrating steps in a method for checking atire pressure.

FIG. 21 shows a flow chart illustrating steps in a method for detectinga leak in a pressure vessel.

DETAILED DESCRIPTION

Referring to the drawings, the present invention will be described indetail in view of following embodiments. The following description isnot intended to limit the invention to these preferred embodiments, butrather to enable any person skilled in the art to make and use thisinvention

1. Overview

The tire management system (TMS) can include one or more control valves110 and a check valve 120, and can optionally include an air source 130and an air sink 140. The TMS functions to provide an on-vehicle tireinflation system that automatically fluidly isolates a tire 150 from theinflation system (e.g., air source 130) in the event of a system leak,but still allows controlled tire deflation during typical use. The TMScan further automatically fluidly isolate the tire 150 from theremainder of the fluid circuit (e.g., from other tires connected to thesame fluid circuit) in the event of tire leak, but still allowcontrolled tire inflation during typical use.

The method of TMS operation includes: determining a pressure parametervalue S200, determining an operational parameter for a valve based onthe pressure parameter value S210, and controlling the valve based onthe operational parameter S220. The method functions to selectivelycontrol the TMS system to avoid triggering automatic tire fluidisolation during selective tire deflation and/or inflation.

Variants of the tire management system (TMS) and method confer severalbenefits over conventional tire pressure management systems and methods.First, in some variants, the check valve seals closed at a system leak(e.g. when the vehicle is in a ‘key-off’ state), isolating the systemfrom the tire. These variants can confer the benefit of preventing tiredeflation when the vehicle is parked, which further aligns withregulations regarding minimum required inflation amounts of a tire.Second, in some variants, the system deflates a tire to a target tirepressure through dithering of the control valve. These variants canconfer the benefit of controllably deflating a tire without activating acheck valve seal. Additionally, some variants confer the benefits ofboth the first and second variant, which are traditionally at odds dueto the risk of sealing a check valve during traditional deflation(non-dithered), which could be dangerous to the driver as well asrequire intervention at the tire to unseal the check valve. Fourth, insome variants, the check valve is bidirectional. This can confer thebenefit of isolating the system from the tire in the case of a systemleak as well as isolating the tire from the system in the case of a tireleak (e.g. tire blowout). Fifth, in some variants, the check valve ispassive and/or the control valve is non-proportional, both of which canconfer the benefit of a relatively low cost of manufacture of thesystem.

2. System.

As shown in FIG. 1, the TMS 100 includes a control valve 110 and a checkvalve 120. The TMS 100 can additionally include an air source 130, anair sink 140, a tire 150, a manifold 160, a pressure sensor 170, acontroller 180, a vehicle condition database 185, and/or a mountingmechanism 190. Additionally or alternatively, the TMS 100 can includeany other suitable components. Each TMS can be connected to one or moretires 150 through the same or different manifold in parallel, in series,or a combination thereof. Each vehicle can include one or more TMS′ 100,wherein multiple TMS' can be connected to the same or different tires.Multiple TMSs can optionally share components (e.g., control units),data (e.g., transferred from a first TMS to a second TMS), or any othersuitable element.

2.1 Air System.

The system can further include any or all of an air system, wherein theair system includes the following air system elements: an air source130, an air sink 140, and a tire 150. However, the air system caninclude any other suitable component.

2.2 Air Source.

The air source 130 functions to provide compressed air to a tire in avehicle (e.g. a truck). Preferably, the compressed air is only providedto a tire when the compressed air in the air source is at a higherpressure than the air in the tire. Alternatively, the compressed air canbe provided to the tire at any time. Additionally or alternatively, theair source 130 can function to provide compressed air to other elementsin the system or vehicle (e.g. to the braking system, suspension system,etc.). Preferably, the air source 130 is fluidly connected to a tire,wherein the air source 130 transmits compressed air to the tire duringtire inflation. Alternatively, the air source 130 can be fluidlyconnected to a pair of tires, all the tires in a vehicle, or any numberor combination of tires. Preferably, the air source 130 is also fluidlyconnected to a compressor, wherein the air source 130 receivescompressed air from the compressor. Additionally or alternatively, theair source 130 can include a compressor and/or be fluidly connected toambient air or any other air source. Further alternatively, the airsource can be fluidly connected or otherwise connected to any othercomponent of the vehicle, an external pump, a conduit inside or outsidethe vehicle (e.g. hose), or any other suitable component. Preferably,the air source 130 is a reservoir of compressed air (e.g. a compressedair tank). Alternatively, the air source 130 is a reservoir ofcompressed fluid, a compressor, a pump, or other suitable device.Preferably, there is a single air source 130 in the TMS 100 system.Alternatively, there can be one air source 130 per tire in the vehicle,one air source 130 among multiple vehicles, or any other arrangement ofthe air source(s) 130. Preferably, the air source 130 containscompressed air at all times of vehicle operation. Alternatively, the airsource 130 can operate between one or more modes. In one variation, themodes are binary, wherein the air source 130 contains compressed air inone mode (e.g. when the vehicle is in a ‘key-on’ state) and contains airat atmospheric pressure in another mode (e.g. when the vehicle is in a‘key-off’ state). In another variation, there can be any number ofoperational modes for the air source 130.

2.3 Air Sink.

The system can further include an air sink 140, which functions toremove air from a tire in a vehicle. Preferably, air is only removedfrom a tire when the air in the tire is at a higher pressure than air inthe air sink 140. Alternatively, air can be transmitted from the tire tothe air sink 140 at any time. Additionally or alternatively, the airsink 140 can function to remove air from other elements in the system orvehicle (e.g. from the engine). Preferably, the air sink 140 is fluidlyconnected to a tire, wherein air flows from the tire to the air sink 140during tire deflation. Alternatively, the air sink 140 can be fluidlyconnected to a pair of tires, a set of tires, or any number orcombination of tires. Preferably, the air sink 140 is or is fluidlyconnected to the ambient environment of the vehicle. Alternatively, theair sink 140 can be fluidly connected or otherwise connected to afilter, a reservoir/tank, a conduit inside or outside the vehicle (e.g.hose), another component of the vehicle, or any other suitable componentor environment. Preferably, the air sink 140 is a conduit (e.g. hose).Alternatively, the air sink 140 is a valve, or any other suitableoutlet. Preferably, there is a single air sink 140 in the TMS 100system. Alternatively, there can be one air sink 140 per tire in thevehicle, one air sink 140 among multiple vehicles, or any otherarrangement of the air sink 140(s). Preferably, the air sink 140 permitsair transmission at all times of vehicle operation. Alternatively, theair sink 140 can operate between one or more modes. The modes can bebinary, wherein the air is open in one mode (e.g. when the vehicle is ina ‘key-on’ state) and is closed in another mode (e.g. when the vehicleis in a ‘key-off’ state). Alternatively, there can be any number ofoperational modes for the air source. In one example, the air sink 140is configured to permit a specified rate of air flow depending on a tirepressure parameter (e.g. pressure value).

2.4 Tire.

The system can further include a tire 150, wherein the tire 150 isattached to the vehicle and functions to provide traction between thevehicle and the terrain over which the vehicle travels. Additionally oralternatively, the tire 150 can function to absorb shock transferred tothe vehicle from the terrain, support the load of the vehicle, and/ordetermine the direction of vehicle travel. Preferably, the tire 150 isattached to the vehicle and fluidly connected to both an air source andan air sink. Alternatively, the tire 150 can be fluidly connected to oneof an air source and an air sink, or neither an air source nor an airsink. In one variation, the tire 150 is fluidly connected to both an airsource and an air sink with a single conduit. In another variation, thetire 150 is fluidly connected to an air source with a conduit and to anair sink with a separate conduit. In one example, the conduit is an axle168 (e.g. a pressurized axle) in a vehicle. In another example, theconduit is a hose assembly (e.g. a pressurized axle tube). Preferably,the tire 150 has a cylindrical shape formed by an external shellconfigured to retain air. Alternatively, the tire 150 can have aspherical shape or any other suitable shape. Preferably, the externalshell is rubber (e.g. synthetic rubber, natural rubber). Alternatively,the external shell can be a fabric overlaid on a wire mesh, a carbonblock compound, or any other material. Preferably, the tire 150 has apattern of grooves (e.g. tread) arranged on all or part of the externalshell which makes contact with the ground. In a cylindrical variation ofthe tire 150, a tread pattern, for example, can be fabricated on theouter wall of the tire 150. Alternatively, a pattern of grooves may bearranged on the entire 150 external shell or on any part of the externalshell. In one variation, the system includes four tires 150 per axle 168of a vehicle. In another variation, the system includes two tires 150per axle 168 of the vehicle. In other variations, the system includes asingle tire 150 or any number of tires 150, arranged in any way withrelation to each other and to the vehicle.

Preferably, the tire 150 further comprises a tire valve 151 configuredto provide an attachment site with which to fluidly connect the tire 150to an air source and/or an air sink. Preferably the tire valve isfluidly connected to an air source or an air sink via an intermediarycomponent (e.g. a conduit), wherein the tire valve is attached to oneend of the intermediary component (e.g. a threaded tube). Alternatively,the tire valve can be directly attached to an air source and/or an airsink. Preferably, the tire valve is a poppet valve (e.g. Schradervalve). Alternatively, the tire valve can be a check valve, a spoolvalve, a plug valve, or any other valve. Preferably, the tire valve isconfigured for two-way air flow, but can alternatively be configured forone-way air flow or any number and arrangement of air flows. Preferably,the tire valve is passive, but can alternatively be actively controlled(e.g. by a control unit). Preferably, each tire 150 has two tire valvesbut can alternatively have a single tire valve or any number of tirevalves.

In one variation, the tire 150 and/or TMS further includes a pressuresensor connected to the tire 150, wherein the pressure sensor isconfigured to determine a pressure parameter of the tire 150 (e.g.pressure value of air within external shell, pressure rate of flowinto/out of tire 150, etc.). In one example, for instance, the pressuresensor is coupled to the tire valve, wherein the value of the pressureparameter measured by the pressure sensor is used, at least in part, todetermine the operational mode of the tire valve (e.g. open, closed,open for a specified direction of flow, etc.). In a second example, thepressure sensor is connected to manifold fluidly connected to the tireinterior. This manifold can be the fluid manifold fluidly connecting thetire 150 to the air source 130, the air sink 140, and/or to any othersuitable endpoint, wherein the tire pressure can be measured by holdingthe tire valve in an open position, sealing an upstream valve, arrangedbetween the tire and the endpoint, and measuring an interstitialpressure. However, the tire pressure can be otherwise determined.

2.5 Manifold.

The system can further include a manifold 160, which functions to directfluid flow between air system elements. Preferably, the fluid flow iscooperatively directed by one or more valves (e.g. control valves), butcan alternatively be directed independently or by any other suitablecomponent. Additionally or alternatively, the manifold 160 functions tocontain (e.g. enclose, mechanically protect) one or more systemcomponents (e.g. control valves, check valves). Additionally oralternatively, the manifold 160 can function as a substrate forattachment of system components and/or external components.

In a first variation, variation, the manifold 160 is a set of one ormore fluid connections, wherein the fluid connections are configured tofluidly connect an air source and an air sink to a tire. The fluidconnections can be flexible, rigid, or have any suitable property. Thefluid connections can be hoses, tubes, lumens (e.g., axle lumens), or beotherwise configured. In one example, one hose connects the tire to anair source while another conduit connects the tire to an air sink. Inanother example, one hose connects the tire to an air source while asecond hose connects the tire to an air sink, wherein the first andsecond hoses are connected with a channel. In one variation in which theTMS is a central tire inflation system, the manifold extends from acentral air source (e.g., air reservoir), through or along the axles, tothe wheel ends. However, the air can be otherwise routed to the wheelends.

In a second variation, the manifold 160 is a centralized air routingcomponent that accepts auxiliary fluid connections to route air to thetires. The manifold 160 is preferably made of a thermoplastic (e.g.,nylon or polyvinyl toluene with a 30% glass fill), but can alternativelybe made of another synthetic or natural polymer, a flexible material(e.g. rubber), metal (e.g., an axle lumen, metal tube, etc.), compositematerial, or any other suitable material. The manifold 160 is preferablyinjection molded, but can alternatively be milled out of a single blockof material (e.g., metal, plastic), cast out of metal, composed ofseparate sub-components which are fastened together, or made using anycombination of these or other suitable manufacturing techniques.

The manifold 160 may define one or more ports 114 a, 114 b, 114 c, 114d, which function to fluidly connect the air system elements. The ports114 a, 114 b, 114 c, 114 d can also function to receive an externalfitting and/or attachment (e.g. a threaded quick-release compressed-gasfitting, barbed fitting, hose, pressurized axle tube, etc.) thatfacilitates fluid connection of the port to the air system element. Inone variation, each air system element has its own port. In othervariations, a single one of the ports 114 a, 114 b, 114 c, 114 d may beshared among multiple air system elements. In other variations, a singleair system element is connected to multiple ports 114 a, 114 b, 114 c,114 d. The port preferably defines a straight flow axis, but canalternatively define a curved flow path, a branched flow path (e.g.,with at least a third end in addition to the first and second end), orany other suitable path along which air can flow through the port. Invariations including a plurality of ports 114 a, 114 b, 114 c, 114 d,the flow axis of each port 114 a, 114 b, 114 c, 114 d may be parallel toeach of the other flow axes of each of the other ports 114 a, 114 b, 114c, 114 d. In one example, the first and second ports 114 a, 114 b arearranged with the respective flow axes sharing a common plane (portplane). However, multiple ports can be arranged offset from each other,at a non-zero angle to each other, or be arranged in any other suitableconfiguration.

The manifold 160 preferably includes a channel 161 (galley) whichfunctions to provide fluid connections between ports, but can beotherwise configured. The channel 161 preferably contains compressed airfrom the air source that is simultaneously accessible to each of thecontrol valves (e.g., is connected to the control valves in parallel),but can be serially connected to the control valves or otherwiseconnected. The channel 161 preferably intersects the ports between therespective first and second ends of each port, but can alternatively beconnected by a secondary manifold 160 or otherwise connected to one ormore ports of the manifold 160. The channel 161 is preferably fluidlyconnected to every port of the manifold 160, but can alternatively beconnected to a first subset of ports and fluidly isolated from a secondsubset of ports. In one variation, the channel 161 connects one port toa second port. The pressure sensor is preferably fluidly connected tothe channel 161 and measures the pressure of whichever downstreamelement is fluidly connected to the channel 161, but can alternativelybe arranged within a port, along a fluid connection, or be otherwisearranged. The channel 161 preferably extends normal the port, but canalternatively extend parallel to or at any other suitable angle to theport. The channel 161 preferably lies in the same plane as the ports,but can alternatively be offset from the port plane (e.g., lie above orbelow the port plane, extend at an angle to the port plane, etc.). Thechannel 161 is preferably substantially linear (e.g., define asubstantially linear flow axis), but can alternatively be curved (e.g.,toward or away from the second end, out from the port plane, etc.) orhave any other suitable configuration. However, the channel 161 can beotherwise configured or arranged. The channel 161 is preferablyconnected to an output of a filter 162, but can alternatively beconnected directly to an air element.

In a first embodiment, the manifold 160 is the manifold 160 in theelectronically controlled vehicle suspension system in U.S. ProvisionalApplication No. 62/384,652 filed 6-Sep. 2017, which is incorporated inits entirety by this reference. In one example, the manifold 160includes a first port 114 a coupled to an air source, a second port 114b (e.g., exhaust port) coupled to an air sink, and a third port 114 ccoupled to a tire (e.g. through the tire valve), wherein the three ports114 a, 114 b, 114 c are fluidly connected through a single channel. Themanifold 160 can optionally include a fourth port 114 d fluidlyconnected to a suspension system 163 (e.g., air spring). However, anyother suitable manifold 160 can be used.

2.6 Control Valve.

The control valves 110 may function to selectively bring a tire 150 intofluid connection with one or more air system elements (e.g. FIGS.3A-3D). In some embodiments, the control valves 110 each include atwo-way valve. Alternatively, one or more of the control valves 110 mayinclude a three-way valve, or can have any number of inlets and outletsin any arrangement. The control valves 110 may be operable between anopen position, permitting fluid connection between a tire 150 and an airsystem element, and a closed position, wherein the control valve 110prevents fluid connection between a tire 150 and an air system element.The control valves 110 may be normally in (i.e. biased toward) an openposition (e.g., they are normally-open valves). Alternatively oradditionally, one or more of the control valves 110 can be normally in(biased toward) a closed position (e.g., a normally-closed valve). Insome embodiments, one or more of the control valves 110 may be activelycontrolled (e.g. by a controller). Alternatively or additionally, one ormore of the control valves 110 may be passively operable. For example,the control valves 110 may each include an electromechanically operablevalve (e.g. a solenoid valve). Alternatively, one or more of the controlvalves 110 can be operable in any other way. In some embodiments, thecontrol valves 110 each include a non-proportional valve. Alternatively,one or more of the control valves 110 can include a proportional valve,a servo valve, or any other type of valve. In one variation, the controlvalves 110 each include the actuator as described in U.S. ProvisionalApplication No. 62/384,652 filed 6 Sep. 2017, which is incorporated inits entirety by this reference.

In some embodiments, one or more of the control valves 110 are emplacedin (e.g. arranged in) a flow path (e.g. a port) between a tire 150 andone or more air system elements, and controls fluid flow therethrough.Preferably, the control valve 110 is aligned with the flow path but canalternatively be oriented at an angle with respect to the flow path,located partially or wholly outside the flow path, or otherwisearranged. Preferably the TMS has one control valve 110 per air systemelement, but can alternatively have any number of control valves 110.

In one variation, the control valves 110 are arranged in a manifold 160(e.g. FIG. 4). In a first example, the control valves 110 are arrangedin the manifold 160 described in U.S. Provisional Application No.62/384,652 filed 6 Sep. 2017, which is incorporated in its entirety bythis reference, wherein the control valves 110 are arranged in ports,wherein each port is fluidly connected to a channel 161. In anotherexample, the control valves 110 are arranged in a manifold 160 without achannel 161, wherein the fluid connections between air system elementsremain separate.

In one variation, wherein the control valves 110 are arranged in themanifold as described in U.S. Provisional Application No. 62/384,652filed 6 Sep. 2017, which is incorporated in its entirety by thisreference, wherein the manifold has a channel 161, there is one controlvalve 110 per air system element.

For example, and as shown in FIG. 3C, the control valves 110 include anintake valve 111) which fluidly connects an air source 130 to thechannel 161. As also shown in FIG. 3C, the control valves 110 may alsoinclude an exhaust valve 112 which fluidly connects an air sink 140 tothe channel 161. The exhaust valve 112 can be normally-open, such thatthe system is exhausted upon key-off. Alternatively, the exhaust valve112 may be a normally-closed valve. The intake valve 111 can benormally-closed, such that initial system operation does not immediatelypressurize the channel 161. Alternatively, the intake valve 111 may be anormally-open valve. The intake valve 111 can selectively control thepressure in a fluidly connected third port 114 c (connected to the tire150), and thereby control a tire pressure in one or more tires 150fluidly connected to the third port 114 c. As also shown in FIG. 3C, thecontrol valves 110 may also include an output control valve 113 whichfluidly connects one or more tires 150 to the channel 161. In thisvariation, the intake valve 111 and the output control valve 113 can beopened to inflate the tire 150, and the exhaust valve 112 and the outputcontrol valve 113 can be opened to deflate the tire 150. By selectivelycontrolling the configurations of these control valves 111, 112, 113,the tire(s) 150 can be in fluid communication with only the air sink 140(e.g. during deflation), only the air source 130 (e.g. duringinflation), both the air sink 140 and the air source 130, or neither theair sink 140 nor the air source 130. An example of a flow path duringtire deflation is illustrated in FIG. 5A. An example of a flow pathduring tire inflation is illustrated in FIG. 5B.

2.7 Pressure Sensor.

The system can further include a pressure sensor 170, which functions todetermine a pressure parameter value in the TMS or elsewhere in thevehicle. Preferably, the pressure sensor 170 is a differential pressuresensor 170 but can alternatively be a gauge pressure sensor 170, anabsolute pressure sensor 170, a sealed pressure sensor 170, or any othersensor configured to determine a pressure parameter. Preferably, thepressure parameter is a pressure change rate between air systemelements. Alternatively, the pressure parameter can be a pressure changerate within an element, a gauge pressure within an element, a differencein gauge pressures between elements, a pressure change acceleration, orany other suitable parameter. The pressure sensor 170 is preferablyconnected to and configured to measure a pressure parameter in an airsystem element (e.g. an air source, a tire, an air sink), but canalternatively be configured to measure a pressure parameter in amanifold (e.g. in a channel, port, etc.), between air system elements,or elsewhere. Preferably, the pressure sensor 170 is a piezoelectricmaterial, but may be any other material or combination of materialsconfigured to determine a pressure parameter. Preferably, there is onepressure sensor 170 per air system element, but alternatively there maybe a single pressure sensor 170 or any number of pressure sensors 170 inthe system.

In one variation, a pressure sensor 170 is arranged in a port of amanifold, wherein the pressure sensor 170 port is fluidly connected to achannel and configured to determine the value of a pressure parameter inthe channel 161. In one example, the pressure sensor 170 measures theabsolute pressure of the compressed air in the channel 161. In anotherexample, the pressure sensor 170 measures the pressure change ratebetween an air source and a tire 150. In alternative examples, thepressure sensor 170 can be arranged in any port, channel, or other partof a manifold, wherein the pressure sensor 170 can measure any pressureparameter associated with any air system element or combination of airsystem elements fluidly connected to said element.

In a second variation, the pressure sensor 170 is arranged within orelsewhere on an air system element. In one embodiment, a pressure sensor170 is arranged within the external shell of a tire and configured tomeasure the absolute pressure within the tire. In a second embodiment, afirst pressure sensor 170 is arranged within a first air system element(e.g. an air source) and a second pressure sensor 170 is arranged withina second air system element (e.g. a tire), wherein the pressure sensors170 are each configured to determine a pressure parameter (e.g. absolutepressure), wherein these pressure parameters are further used todetermine a secondary pressure parameter (e.g. pressure change rate). Inone example, the secondary pressure parameter is determined using acontroller.

In some embodiments, and as shown in FIG. 3C, the system includes apressure control module (PCM) 164. The PCM 164 includes a pressuresensor 170 fluidly connected to and monitoring the pressure within asuspension system 163 (e.g., an air spring). In one example, thepressure sensor 170 is used to determine the load in the vehicle.However, the system can include any suitable number of pressure sensorsarranged in any suitable configuration. In some embodiments, the PCM 164also includes the manifold 160, and one or more control valves 110 in aunitary package.

2.8 Electronic Control Unit.

The system can further include an electronic control unit (ECU) 180,which functions to control the operation of one or more valves. The ECU180 may include one or more microprocessors and/or microcontrollers.Additionally, the ECU 180 may include communications circuitry, such asCAN, LIN, Ethernet, etc. Additionally, the ECU 180 may include digitaland/or analog output circuitry for providing power to operate one ormore valves. Additionally or alternatively, the ECU 180 can function tocontrol power provision to one or more valves in the system.Additionally or alternatively, the ECU 180 can function to control theoperation of or the power provision to any element or combination ofelements in the system or vehicle (e.g. a pressure sensor). In someembodiments, the PCM 164 also includes the ECU 180.

The ECU 180 is preferably electrically connected to and controls theoperation (e.g. position) of one or more control valves. The ECU 180 canstore a vehicle condition database 185, an error log, or any othersuitable information. Alternatively, the ECU 180 can be wirelesslyconnected to and control the operation of one or more control valves.The ECU 180 is preferably a printed circuit board assembly (PCB), butcan alternatively be a wire wrap circuit, a point-to-point solderedelectrical circuit, or any other suitable configuration. In onevariation, the ECU 180 is configured for wireless communication, and caninclude short range communication systems (e.g., NFC, Bluetooth, RF,etc.), long-range communication systems (e.g., WiFi, cellular,satellite, etc.), a vehicle networking system (e.g., CAN busconnection), or any other suitable communication system. In one example,the ECU 180 is configured to receive instructions from a driver, a fleetcommand center, or any other suitable control system.

In one variation, the ECU 180 is configured to communicate with a remoteinformation source (e.g. lookup table, database, server, user device,vehicle network system, etc.), wherein the remote information sourcecommunicates commands for the operation of one or more control valves tothe ECU 180. In one example, the remote information source communicatesa set of commands for the control valves to the ECU 180, wherein the setof commands is determined using vehicle information such as the load(e.g., mass) value and distribution in the vehicle, the terrainconditions (e.g., current and/or anticipated), the location andorientation of the vehicle, and/or any other parameter. In anotherexample, the remote information source is an operator at a fleet commandcenter, wherein the operator communicates instructions to a driverthrough a display module coupled to the ECU 180.

In one variation, the ECU 180 is an electronics module as described inU.S. Provisional Application No. 62/384,652 filed 6 Sep. 2017, which isincorporated in its entirety by this reference. In a second variation,the ECU 180 is a user device (e.g. mobile phone). In a third variation,the ECU 180 is an existing control unit (e.g. engine control unit) inthe vehicle.

2.9 Vehicle Condition Database.

The system can further include a vehicle condition database 185, whichfunctions to store vehicle condition parameters, such as, but notlimited to: operational parameters (e.g. operational modes for a controlvalve or a check valve), pressure parameters, tire condition (e.g.wear-and-tear) parameters, or any other parameter. Additionally oralternatively, the vehicle condition database 185 can function to informthe operation of one or more valves based on the vehicle conditionparameters. For example, the vehicle condition database 185 can includea database, table, equation, or other data structure correlating apressure or pressure rate differential to control valve operatinginstructions. In a second example, the vehicle condition database 185includes a data structure (database, equation, lookup table, etc.)correlating the load magnitude and/or distribution with target tirepressures (e.g., for all or a subset of tires). In a third example,vehicle condition database 185 includes a data structure correlating aterrain parameter (e.g., incline, surface roughness, surface looseness,surface wetness, traction, etc.) with target tire pressures (e.g., forall or a subset of tires). However, the vehicle condition database 185can include any other suitable information.

Preferably, the vehicle condition database 185 is communicativelycoupled to a controller of the vehicle, but can additionally oralternatively be communicatively coupled to a user device of an operatorof the vehicle (e.g. driver, fleet command center, etc.), or any othersuitable device. The set of vehicle condition parameters preferablyincludes parameters related to the state of the vehicle, such as theload (magnitude, distribution, etc.) on the vehicle, vehicle ‘health’(e.g. wear-and-tear, service reports, oil and fuel levels, etc.), andany other information related to the operation of the vehicle.Additionally or alternatively, the set of vehicle condition parameterscan include parameters related to the environment of the vehicle along aroute, such as, but not limited to: weather conditions (e.g.temperature, precipitation), traffic conditions, terrain conditions(e.g. road incline angle, predicted road friction, etc.), or any otherconditions related to the current or proposed environment of a vehicle.Preferably, the vehicle condition database 185 is dynamically updatedbut can alternatively be updated at one or more discrete times, orcontain static, predetermined parameters.

In one variation, the vehicle condition database 185 includes a lookuptable, which functions inform the operational parameters of the vehicle.To perform this function, the lookup table correlates operational modesof one or more valves in the vehicle with vehicle condition parameters.Additionally or alternatively, the lookup table can correlateoperational modes of other elements of the system or vehicle (e.g.vehicle key-on/off state) with vehicle condition parameters. Preferably,the correlations are determined through one or more algorithms, but canadditionally or alternatively be determined through a mathematicalmodel, through a machine learning process, by an operator, or determinedin any other suitable way. In one example, the lookup table contains aset of potential arrangements of a load on a vehicle, a target pressureparameter for each tire based on that load, and an operational mode foreach valve in the system, wherein the operational mode is determinedalgorithmically based on the target tire pressure parameters and thecurrent tire pressures parameters.

2.10 Check Valve.

The check valve 120 functions to selectively isolate a tire from fluidconnection with one or more air system elements. Preferably, the checkvalve 120 is fluidly connected to a tire and to a control valve, but canalternatively be fluidly connected just to a tire. Preferably, the checkvalve 120 is arranged upstream of a tire, but can alternatively bearranged downstream of a tire, within a tire, or otherwise arranged. Thecheck valve 120 is preferably arranged downstream of one or more controlvalves, but can alternatively be arranged within a control valve,upstream of a control valve, or otherwise arranged. The check valve 120can be passively controlled (e.g., based on pressure differentialsacross the valve, pressure rate changes across the valve, etc.),actively controlled by the ECU, or otherwise controlled.

In a first variation, the check valve 120 is a one-way check valve,arranged within the fluid manifold leading to the tire. The check valve120 can be unidirectional (e.g., permit fluid flow in a singledirection), bidirectional (e.g., permit fluid flow in both directions),or otherwise configured. In a first embodiment, the check valve can bean unloader valve that fluidly seals (e.g., upstream, toward the system)in response to the upstream pressure (e.g., system pressure) fallingbelow the downstream pressure (e.g., tire pressure) by a thresholdamount, at a rate faster than a predetermined rate, when the downstreampressure substantially matches a target pressure (e.g., a maximum tirepressure), or when any other suitable condition is satisfied. In asecond embodiment, the check valve can fluidly seal downstream, towardthe tire, in response to the downstream pressure falling below theupstream pressure by a second threshold amount (e.g., equal to, lessthan, or more than the first threshold amount), at a rate faster thanthe same or different predetermined rate, or when the same or differentcondition is satisfied. In a third embodiment, the system can includecheck valves of both the first and second embodiment in-line within thefluid manifold leading to the tire.

In a second variation, the check valve 120 is a two-way valve, but canalternatively be a three-way valve or have any number of inlet andoutlet ports. Preferably, the check valve 120 defines a first combinedinlet/outlet port and a second combined inlet/outlet port, wherein thefirst combined inlet/outlet port is fluidly connected to an upstream airsystem element (e.g. air source) and the second combined inlet/outletport is connected to a downstream air system element (e.g. tire).Alternatively, the first combined inlet/outlet port is locateddownstream of the second combined inlet/outlet port, neither combinedinlet/outlet port is located downstream of the other, or they can bearranged in any other suitable way. Preferably, the check valve 120 is abidirectional valve, wherein the check valve 120 is configured tocontrol flow in two directions, wherein the two directions arepreferably arranged opposite to each other but can alternatively beotherwise arranged. Alternatively, the check valve 120 permits fluidconnection between a tire and an air system element, and as many sealedconfigurations as there are directions in which the check valve 120 isconfigured to seal (e.g. two sealed configurations for a bidirectionalvalve, one sealed configuration for a unidirectional check valve 120,etc.), wherein each sealed configuration prevents fluid connection in aspecified direction between a tire and an air system element.Alternatively, the check valve 120 may be operable in only one or moresealed configurations, only an open configuration, or in any combinationof open and sealed configurations.

Preferably, the check valve 120 is in a first sealed configuration (e.g.FIG. 7B) when a pressure parameter value associated with a secondcombined inlet/outlet port exceeds a pressure parameter value associatedwith a first combined inlet/outlet port by a first predeterminedthreshold, herein referred to as the first sealing pressure.Alternatively, the check valve 120 is normally in a first sealedconfiguration, is only in a first sealed configuration for a specifiedrange of pressure parameter values, is never in a first sealedconfiguration, or is in a first sealed configuration at any other time.Preferably, the check valve 120 is in a second sealed configuration(e.g. FIG. 7D) when a pressure parameter value associated with a firstcombined inlet/outlet port exceeds a pressure parameter value associatedwith a second combined inlet/outlet port by a second predeterminedthreshold, herein ref erred to as the second sealing pressure.Alternatively, the check valve 120 is normally in a second sealedconfiguration, is only in a second sealed configuration for a specifiedrange of pressure parameter values, is never in a second sealedconfiguration, or is in a second sealed configuration at any other time.Preferably, the first and second sealing pressures are equal, but canalternatively be different (e.g., the first higher than the second). Inone example, the system enters a sealed configuration when thedownstream pressure (e.g., tire pressure) drops below the upstreampressure (e.g., system pressure) beyond a threshold difference or fasterthan a threshold rate, such as in the case of a tire blowout (e.g. FIG.7B). In this example, the check valve seals toward the secondinlet/outlet port, and functions to isolate the tire from the rest ofthe system. In another example, the system enters a sealed configurationwhen the upstream pressure (e.g., system pressure) drops below thedownstream pressure (e.g., tire pressure) beyond a threshold differenceor faster than a threshold rate, such as when the vehicle is in akey-off state to prevent tire deflation (e.g. FIG. 7D) while the vehicleis parked or when the compressor is turned off. In this example, thecheck valve seals toward the first inlet/outlet port, and functions toisolate the system from the tire. Preferably, the check valve 120 is inan open configuration (e.g. FIGS. 7A and 7C) when the difference betweena pressure parameter value associated with a first combined inlet/outletport and a pressure parameter value associated with a second combinedinlet/outlet port is below both the first and second sealing pressures.Alternatively, the check valve 120 is in an open configuration when thedifferent in pressure parameter values is only below a single sealingpressure, when the difference in pressure parameter values is zero,check valve 120 is normally in a first sealed configuration, when thedifference in pressure parameter values is within a specified range, orat any other time. Preferably, the operation of the check valve 120 ispassively controlled but can alternatively be actively controlled (e.g.by the ECU 180).

In one variation, the operational mode of the check valve 120 furtherincludes a partially sealed configuration, wherein fluid flow within thevalve is partially restricted. In one example, the degree of flowrestriction is proportional to the difference in pressure parametervalues between valve ports.

Preferably, the check valve 120 (e.g. FIG. 6) includes a closing element121, wherein engagement of the closing element 121 with an inlet/outletport of the check valve 120 functions to restrict or prevent flowthrough that inlet or outlet port. Alternatively, the check valve 120can include no closing element 121, two closing elements 121, or anynumber of closing elements 121. Preferably, the closing element 121 is apoppet, but can alternatively be a ball, disk, diaphragm, gate, or anyother element. Preferably, the closing element 121 is rubber, but canalternatively be metal, plastic, glass, compressed fluid, or anysuitable material. The inlets and outlets of the check valve 120 arepreferably conically tapered to retain the closing element 121;alternatively, the check valve 120 can have inlets and outlets withuniform cross sections or any other suitable cross section. The checkvalve 120 preferably further includes a compressive element 122, whereinthe compressive element 122 functions to press a closing element 121against an inlet or an outlet port of the valve in the closedconfiguration. Alternatively, the check valve 120 can include onlyclosing elements 121. Preferably the compressive element 122 is a springbut can alternatively be a piston, a column of compressed air, or anyother suitable element. Preferably each compressive element 122 in thecheck valve 120 has the same compressive value (e.g. spring constant),but can alternatively have different compressive values. Preferably, allthe elements of the check valve 120 are enclosed within a single housingbut can alternatively be split among multiple housings or not enclosedin any housing.

Preferably, the check valve 120 is arranged in alignment with a flowaxis between a tire and an air system element. Alternatively, the checkvalve 120 may be arranged with an offset to the flow axis, arranged atan angle with respect to the flow axis, or otherwise arranged.

In one variation, the check valve 120 includes one closing element andtwo compressive elements. In one example, a first closing element iscoupled to the first inlet/outlet port, a second closing element iscoupled to the second inlet/outlet port, and the closing element isarranged between the two compressive elements.

In a second variation, the check valve 120 includes two closing elementsand two compressive elements. In one example, the closing elements arearranged closest to the check valve 120 inlet/outlet ports with thecompressive elements arranged between the closing elements.

In a third variation, the check valve 120 is a set of two or moreunidirectional check valves 120. In one example, the unidirectionalcheck valves 120 are arranged in series. In another example, theunidirectional check valves 120 are arranged in parallel.

2.11 Mounting Mechanism.

The system can further include a mounting assembly, wherein the mountingmechanism 190 functions to connect all or part of the system to avehicle. Additionally or alternatively, the mounting mechanism 190 canfunction to enclose any or all parts of the system, as well as otherelements of a vehicle. The mounting mechanism 190 is preferably attachedat a wheel assembly of a vehicle but can alternatively can be attachedat any part of the vehicle (e.g. a manifold). The mounting mechanism 190is preferably attached at the wheel assembly of a vehicle, wherein thewheel assembly includes a hubcap 195 and a tire, but can alternativelybe attached elsewhere in or on a vehicle. The mounting mechanism 190 ispreferably configured to be retrofittable, wherein the mountingmechanism 190 can be attached to existing attachment sites of thevehicle (e.g. a port on a hubcap 195 of the vehicle), but canalternatively require additional components for attachment, canintegrated with the vehicle during manufacture, or integrated in anyother suitable way.

The mounting mechanism 190 preferably includes a mounting conduit 196,wherein the mounting conduit 196 functions to fluidly connect themounting mechanism 190 to the air system of the vehicle. The mountingconduit 196 is preferably connected to an axle of a vehicle (e.g. with abarbed press-in interface), but can alternatively be connected to a hoserunning through an axle, a conduit outside of an axle, or to any othersuitable element. The mounting conduit 196 is preferably a cylindricalshell (e.g. hose, tube), but can alternatively have an obloid crosssection, a non-uniform cross section throughout its length, or any othersuitable geometry. The mounting conduit 196 is preferably metal, but canalternatively be plastic, rubber, or any other suitable material. Thereis preferably one mounting conduit 196 per mounting assembly, but canalternatively be one mounting conduit 196 per air system element, onemounting conduit 196 per subset of air system elements, or any numberand arrangement of mounting conduits. The mounting conduit 196 ispreferably always open but can alternatively be partially open,partially or fully closed, or operate m any number and type ofoperational modes.

The mounting mechanism 190 can further include an attachment piece 191,which functions to connect the mounting conduit to an axle of thevehicle. Preferably, the attachment piece 191 is configured to preventrelative rotation between the axle and the mounting conduit but canalternatively allow partial or full rotation between the axle and themounting conduit. In one variation, the attachment piece 191 is a barbedpress-in interface with spring clamp retention (e.g. FIG. 10). However,the system can include any other suitable attachment piece 191.

The mounting mechanism 190 can further include a rotational assembly192, which functions to provide a fluid connection between the mountingmechanism 190 and the tire of a vehicle. Additionally or alternatively,the rotational assembly 192 can function to enclose one or more checkvalves or other components. The rotational assembly 192 preferablyattaches to a tire at one or tire valves (e.g. Schrader valve), but canalternatively be fluidly connected with one or more tires in anysuitable way. The rotational assembly 192 preferably connects to therest of the mounting mechanism 190 at hubcap 195, but can alternativelyconnect to the rest of the mounting mechanism 190 at any other part of awheel assembly. The rotational assembly 192 preferably includes a seriesof conduits 193 arranged perpendicular to the mounting conduit.Alternatively, the rotational assembly conduits 193 can be arranged atan angle with respect to the mounting conduit or in any other suitablearrangement. The rotational assembly 192 is preferably metal, but canalternatively be plastic, rubber, or any other suitable material.Preferably, the rotational assembly 192 is configured to rotate with thewheel assembly but can alternatively be configured to rotate with anoffset to the wheel assembly, to not rotate at all, or to rotate in anyother way. Preferably, one or more check valves is arranged in eachconduit of the rotational assembly 192, wherein the check valves arealigned with the flow axis defined by the conduit. Alternatively, theremay be no check valves arranged within a conduit, or the check valvesmay be aligned at an angle with the conduit.

The rotational assembly 192 can further include a rotary union 194,wherein the rotary union 194 functions to fluidly connect the rotationalassembly 192 and the mounting conduit, wherein the rotary union 194 isconfigured to preserve a fluid connection between two elements having arelative rotation with each other. Preferably, the rotary union 194 isaligned with the flow axis of the mounting mechanism 190 but canalternatively be aligned with a flow axis of the rotational assembly orotherwise arranged. In one example, the rotary union 194 rotates about astator 197 (e.g., mounting conduit), wherein the stator 197 can remainstatic relative to the vehicle frame. The stator 197 can terminatebefore, at, or beyond the bearing plane of the rotary union. The stator197 is preferably fluidly connected (e.g., along an end, through axialholes, etc.) to the tire conduit (e.g., fluid connection extendingbetween the stator 197 and the tire interior), which can be supported byand/or statically mounted to the rotary union, to a wheel, to the hub,or to any other suitable rotatable wheel component. The tire conduit canbe a T-junction (e.g., wherein each arm can be connected to a tire), acable, or be any other suitable fluid connection to the tire. The tireconduit can be arranged external the wheel hub, within the wheel hub,integrated with the hub, or otherwise arranged. The check valve ispreferably arranged within the tire conduit, but can be arrangedelsewhere.

In one variation, the rotary union 194 is configured to allow formisalignment, runout, and/or any other offset between the mountingconduit and the rotational assembly. An example of a rotary union 194configured to allow for misalignment is shown in FIG. 12.

In one variation, the rotary union 194 further includes one or moreseals 166 and one or more bearings 167 that function to fluidly seal thestator-tire conduit interface and facilitate assembly rotation relativeto the mounting conduit. In one example, the rotary union 194 has a sealarranged around the surface of the mounting conduit, wherein the seal isarranged next to a bearing (e.g. FIG. 10). In another example, therotary union has a seal (e.g. an elastomer seal) arranged between aninner and outer bearing (e.g. FIG. 11).

The rotational assembly 192 can further include any number andarrangement of additional components, such as but not limited to: seals,bearings, retaining rings, attachment pieces, purge channels, andhousings.

In one variation, the mounting mechanism 190 is arranged in a teeassembly 165 (e.g. FIG. 8), wherein the rotational assembly 192 isarranged along a single axis, which is oriented perpendicular tomounting conduit. In one example, shown in FIG. 8, the rotationalassembly attaches to two tire valves. In another example, the rotationalassembly attaches to one tire valve. In another example, shown in FIG.9, the mounting mechanism is configured to interface with hubcaps havinga 1.125-inch vent with a radial O-ring seal, the radial O-ring sealhaving a threaded interface to all locking and rigid clamps to interfacewith varying hubcap thicknesses.

3. Method.

The method for managing a tire functions to enable dynamic control ofair flow into and out of a tire. As shown in FIG. 2, the methodincludes: determining a pressure parameter value S200, determining anoperational parameter for a valve based on the pressure parameter valueS210, and controlling the valve based on the operational parameter S220.The method can further include communicating the state of the system toa remote entity S230.

The method is preferably performed by, using, and/or in cooperation withthe tire management system described above. However, the method canalternatively be performed using any other suitable tire or vehiclemanagement system, such as that disclosed in U.S. ProvisionalApplication No. 62/384,652 filed 6 Sep. 2017, which is incorporatedherein in its entirety by this reference. Additionally or alternatively,the method can be performed with a user device, a remote computingsystem (e.g. a server), or any other suitable computing system.

In one example, the method includes: determining a target deflated tirepressure; dynamically cycling a control valve, fluidly connected betweenthe tire and an air sink, between an open and closed position (e.g., insitu, while the vehicle is in motion); monitoring a pressure change ratewhen the control valve is in the open position; determining controlvalve cycling parameters (e.g., cycling frequency, open duration) basedon the pressure change rate; cycling the control valve according to thecycling parameters until the current tire pressure substantially matchesthe target tire pressure; and in response to upstream system exhaustion(e.g., pressure drop beyond a threshold rate), automatically (e.g.,passively or actively) sealing a check valve arranged within a fluidmanifold between the control valve and the tire. Alternatively, thecycling parameters can be predetermined. This example can optionallyinclude determining an instantaneous tire pressure; determining adeflation duration based on the cycling parameters and the differencebetween the target tire pressure and the instantaneous tire pressure;and cycling the control valve for the deflation duration. A similarprocess can be used to inflate the tire in-situ, wherein the controlvalve can be fluidly connected between the tire and a pressurized airsource.

3.1 Determining a Pressure Parameter Value.

Determining a pressure parameter value S200 functions to assess thecurrent state of the system. The pressure parameter can be the elementpressure (e.g., compressor pressure, tire pressure, ambient pressure), apressure differential between two or more points (e.g., pressuredifference between the tire and compressor), a pressure change (e.g.,the pressure increase or decrease over a period of time), a pressurechange rate (e.g., how fast the pressure is increasing or decreasing),or be any other suitable pressure parameter. The pressure parametervalue can be: calculated, measured, estimated, predicted, selected, orotherwise determined. Additionally or alternatively, determining apressure parameter value functions to specifically assess the currentstate of a tire (e.g. overinflated, underinflated). Preferably thepressure parameter value is determined using one or more pressuresensors (e.g., as described above), but can alternatively be determinedby another type of sensor (e.g. temperature sensor), a visual means(e.g. an image of a tire), a volume assessment (e.g. volume of a tire),or any other device or method. The pressure parameter value ispreferably determined during the key-on state of a vehicle but canalternatively be determined during the key-off state. The pressureparameter value is preferably determined dynamically. In one variation,the pressure parameter value is determined continuously. In a secondvariation, the pressure parameter value is determined at a discrete setof times. In a third variation, the pressure parameter value isdetermined at or after the detection of a specific event (e.g. aspecific terrain type, a change in vehicle load, a threshold inclinelevel, a particular weather condition, key-on or key-off state of thevehicle, etc.). In a fourth variation, the pressure parameter value isdetermined upon command by an operator of the vehicle (e.g. a driver,fleet command center operator, etc.). Alternatively, the pressureparameter value can be determined at any suitable time.

Preferably, more than one pressure parameter value is determined at agiven time. Alternatively, a single pressure parameter value or nopressure parameter value can be determined. Preferably, the pressureparameter value is determined at an air system element (e.g. a tire).Additionally or alternatively, the pressure parameter value (e.g.pressure change rate) is determined between air system elements, betweenan air system element and another element (e.g. atmosphere), between anysuitable elements in a vehicle, or at a remote location (e.g.cloud-based server, fleet command center, etc.). Further alternatively,the pressure parameter value can be determined at any of the locationsdescribed above, or at any other suitable location. In one variation,the pressure parameter value in a manifold is determined (e.g. from apressure sensor coupled to the channel of the manifold).

Determining a pressure parameter value can additionally or alternativelybe performed by or in conjunction with an ECU (e.g. processor). In onevariation, the pressure parameter value is determined through acalculation. In one example, the pressure parameter value is calculatedas the difference between two or more pressure parameter values, whereinthe two or more pressure parameter values are taken at different timesand/or at different locations in the system. In another variation, thepressure parameter value is estimated using an algorithm of the ECU(e.g. a machine learning algorithm). In another variation, the pressureparameter value is approximated from another pressure parameter value(e.g. a pressure parameter value determined earlier) based onpredetermined thresholds and/or models.

The method can further include dynamically determining, monitoring, andor/recording a pressure parameter value.

The method can further include determining a target pressure parametervalue, wherein the target pressure parameter value can be determinedfrom a lookup table, calculated (e.g., using a predictive model, anyother suitable equation, etc.), predicted using a deep learningalgorithm, retrieved from a database (e.g. vehicle condition databasedescribed above), determined by an operator of the vehicle, or otherwisedetermined. The target pressure parameter can be a target tire pressure,a target manifold pressure, or a target pressure associated with anyelement in the system or vehicle. The target pressure parameter valuecan include: a target pressure, a target pressurization rate, apressurization duration, or any other target parameter. The targetpressure can be predetermined, determined once, iteratively determined(e.g., based on new, up-to-date measurements), or determined at anysuitable frequency or time. In one example, different load magnitudesand/or distributions can be associated with different target tirepressures (e.g., wherein the associated target tire pressures can beempirically determined, manually determined, or otherwise determined).In a second example, different pressure differences between the targettire pressure and the current tire pressure can be associated withdifferent pressurization rates and/or durations. In a third example,different pressure differences between the current tire pressure and theair source pressure can be associated with different pressurizationrates, check valve operation parameters (e.g., cycling frequencies, openduration, etc.), and/or pressurization durations. However, the targetpressure parameter can be otherwise determined.

In one variation, a pressure parameter value is determined afteractivating a specified set of operational modes for one or more controlvalves, wherein the operation of the control valves functions toselectively isolate elements coupled to those control valves fromcontributing to the pressure parameter value. In one example, forinstance, a pressure parameter value for the tire alone is measured inthe channel by assigning a closed configuration to the control valvesarranged between the channel and any element other than a tire.

3.2 Determining an Operational Parameter for a Valve Based on thePressure Parameter Value.

Determining an operational parameter for a valve based on the pressureparameter value S210 functions to specify a future configuration of thesystem. The operational parameters preferably include the operationalmodes of the control valves, as described above. Additionally oralternatively, the operational parameters can include the operationalmodes of the check valves. Further additionally or alternatively, theoperational parameters can include a duration for which an operationalmode persists, a transition between operational modes, a frequency (e.g.pulse repetition frequency) of the transition between operational modes,or any other parameter.

Preferably, the operational parameter is determined by an ECU (e.g.microcontroller), wherein the ECU is coupled to one or more valves.Alternatively, the operational parameter is determined from a remoteinformation source (e.g. lookup table) as described above, calculated inconjunction with a remote server, predetermined by the system, predictedusing machine learning, determined in accordance with anotheroperational parameter, determined using any of the methods in S200, orotherwise determined.

S210 is preferably performed after S200, but can alternatively beperformed before S200, wherein S200 serves as a check to see if the restof the method can be eliminated in the absence of S200 (e.g. when theoperational parameters are predetermined), for instance.

In one variation, an operational parameter is determined based on atarget pressure parameter value. In a first example, for instance, whenthe target tire pressure is higher than the current tire pressure, acontrol valve is assigned to operate in an open configuration, whereinthe open configuration permits air flow from an air source to the tire.In a second example, wherein the pressure change rate over time is foundto be constant, all the control valves in the system are assigned tooperate in an open configuration.

In a second variation, the operational parameter includes a temporalcomponent (e.g. a specified frequency, duration, etc.). In one example,the operational parameter for a control valve prescribes that thecontrol valve alternates between an open and a closed configuration witha prescribed pulsing frequency during tire inflation (e.g. FIG. 7A),tire deflation (e.g. FIG. 7C), or at any other time. This operationalparameter, wherein the control valve alternates between operationalmodes, can, for instance, maintain a low pressure differential across acheck valve and function to prevent the check valve from sealing,wherein the check valve is in fluid communication with the controlvalve. In a second example, the operational parameter for a controlvalve prescribes an operational mode and a duration for which theoperational mode will be assigned to the control valve. The specificduration can, for instance, be dynamically determined based on themagnitude of one or more pressure parameter values (e.g. magnitude ofthe pressure change rate at a tire). In another instance, the durationis predetermined.

The cycling frequency can be between 0.5 Hz-5 Hz, higher than 5 Hz,lower than 0.5 Hz, 2 Hz, or be any other suitable frequency. In oneexample, the cycling frequency and open duration per cycle can bepredetermined, wherein the cycling duration can be determined based onthe difference between the current tire pressure and the target tirepressure. In a second example, the larger the pressure differencebetween the tire and the endpoint (e.g., air source or air sink), thehigher the control valve cycling frequency and shorter the open durationper cycle, wherein the cycling frequency can be lowered and/or the openduration per cycle can be shortened as the pressure difference drops. Inthis example, the cycling frequency and/or open duration can be selectedbased on the instantaneous, past, or anticipated pressure differential.In a third example, the higher the pressure change rate, the higher thecontrol valve cycling frequency and/or shorter the open duration percycle, wherein the cycling frequency can be lowered and/or the openduration per cycle can be shortened as the pressure change rate drops.However, the control valve operation parameters can be otherwisedetermined.

3.3 Controlling the Valve Based on the Operational Parameter.

Controlling the valve based on the operational parameter S220 functionsto activate a specified system configuration. The valves are preferablythe control valves discussed above, more preferably the control valvefluidly connected to the tire port (e.g., the third control valve), butcan alternatively be any other suitable valve. Preferably, the specifiedsystem configuration is selected based on one or more of: optimal tireperformance, minimal tire wear-and-tear, and optimal vehicle safety, butcan alternatively be predetermined or selected for in any suitable wayby any suitable means.

Preferably, the valve is controlled by a controller (e.g. electroniccontrol unit), wherein the controller is electrically connected to thevalve. Additionally or alternatively, the valve can be controlled by acontroller not electrically connected to the valve (e.g. processor in auser device, remote server, etc.). Additionally or alternatively, one ormore valves can be passively controlled. In one variation, a valve ismechanically controlled by a pressure differential between the valve'sinlet and outlet.

Preferably, the valves are controlled based on operational parametersdetermined in S210, but can additionally or alternatively be operated inany suitable way. Preferably, S220 is performed after S210, but canadditionally or alternatively be performed at any point in the method.In one variation, S210 and/or S220 are performed multiple timesthroughout the method in order to dynamically manage tire pressureduring the operation of the vehicle. The valves are preferablycontrolled during vehicle operation (e.g., while the vehicle is intransit, being driven, etc.), but can alternatively be controlled at anyother suitable time.

3.4 Communicating the State of the System to a Remote Entity.

The method can further include communicating the state of the system toa remote entity S230, which can function to increase vehicle safetyand/or optimize vehicle performance. Preferably, the remote entity is afleet command center (e.g. FIG. 13), wherein the fleet command centermanages one or more vehicles (e.g. trucks). Additionally oralternatively, the remote entity can be an operator of the vehicle (e.g.driver), a remote server (e.g. database, lookup table), a regulatoryagency, or any other entity. Preferably, S230 is a form of telematics,but can alternatively be any form of telecommunication, localcommunication, etc. Preferably the state of the system includes pressureparameter values, but can additionally or alternatively includeoperational modes of one or more valves, any of the informationdescribed above, or any other information related to the operation of avehicle.

Preferably S230 is performed with a controller of the vehicle, such asany of the controllers described above. Additionally or alternatively,S230 is performed with a user device (e.g. a mobile device), aninteractive device in the vehicle (e.g. a touchpad, button interface,voice-activated speaker system, etc.), or with any other suitable deviceor communication means. Examples of the user device include a tablet,smartphone, mobile phone, laptop, watch, wearable device (e.g.,glasses), or any other suitable user device. The user device can includepower storage (e.g., a battery), processing systems (e.g., CPU, GPU,memory, etc.), user outputs (e.g., display, speaker, vibrationmechanism, etc.), user inputs (e.g., a keyboard, touchscreen,microphone, etc.), a location system (e.g., a GPS system), sensors(e.g., optical sensors, such as light sensors and cameras, orientationsensors, such as accelerometers, gyroscopes, and altimeters, audiosensors, such as microphones, etc.), data communication system (e.g., aWiFi module, BLE, cellular module, etc.), or any other suitablecomponent

Additionally, S230 can be performed in conjunction with one or moresensors (e.g. pressure sensor, accelerometer, etc.). Preferably, S230 isperformed dynamically (e.g. continuously) during the operation of thevehicle, but can alternatively be performed a single time, two or morediscrete times, at the occurrence of an event (e.g. tire pressureparameter value falls below a threshold), at the prompting of the remoteentity, or at any other time.

Preferably, S230 includes the transmission of information (e.g. pressureparameter values, geographic coordinates, etc.) from the vehicle to aremote entity, but can additionally or alternatively include thetransmission of information (e.g. operational parameters) from a remoteentity to the vehicle.

In one variation, S230 includes transmitting pressure parameter valuesto a fleet command center. In one example, the pressure parameter valuesare transmitted dynamically during the operation of the vehicle. In thisexample, the pressure parameter values are monitored at the fleetcommand center. If it is determined by the fleet command center that thepressure parameter values have fallen outside of a suitable range, anotification is sent to the driver of the vehicle (e.g. through a userdevice). Additionally or alternatively, operational commands for thecontrol valves are sent to a controller from the fleet command center.

The method can optionally include probing the fluid system, whichfunctions to determine whether the check valves between the system andeach tire are open. This can be particularly useful during startup,where the check valves can be closed in the upstream direction (e.g.,sealing the tire from the system due to low system pressure). Probingthe fluid system can include: slowly pressurizing the manifoldsconnected to the tires, monitoring the pressure change in the manifoldover time, counting the number of pressure drops, and ceasing manifoldpressurization after the number of pressure drops matches an expectednumber of tires on the vehicle. Probing the fluid system can optionallyinclude: in response to detecting a sealed valve (e.g., valve sealed inthe downstream or tire-side direction), generating and/or transmitting anotification to a user device. The sealed valve can be detected inresponse to: pressurization beyond a threshold time duration, manifoldpressure exceeding a threshold pressure (e.g., less than or equal to thefirst or second sealing pressure), the pressure change rising fasterthan a threshold rate, or otherwise detected.

The method can optionally include monitoring a brake system (e.g., witha secondary pressure sensor), wherein the method is performed after thebrake system has been fully pressurized. The method can optionallyinclude monitoring a fluid suspension system's pressure (e.g., with asecondary pressure sensor), and determining (e.g., calculating,estimating, selecting, etc.) a load magnitude and/or distribution basedon the fluid suspension system's pressure and/or pressure distributionacross the suspension lines. The fluid within the suspension system canbe: a gas, a liquid, a compressible fluid, a noncompressible fluid, aNewtonian fluid, a non-Newtonian fluid, or any other suitable fluid. Inone example, the air suspension system can be fluidly connected to thesame fluid circuit as the TMS, brake system, and/or any other suitablefluid system. However, the system can include any other suitable set ofprocesses.

FIG. 14 shows a block diagram of a tire management system (TMS) 100,including the pressure control module (PCM) 164 configured to inflatefour tires 150 in a vehicle. More specifically, the TMS 100 shown inFIG. 14 includes the PCM 164 in fluid communication with a common header104 that distributes air to each of the tires 150. FIG. 14 also shows acheck valve 120, also called a wheel end check valve (WECV) thatcontrols fluid flow between the common header 104 and each of the tires150.

A problem with conventional central tire inflation systems can arise ifone of the tires 150 has a leak, and air can flow from the other,non-leaking tires 150 air through the open WECVs 120, pressurizing thesystem, and thereby masking the leak. This can occur with bothnormally-open and normally-closed WECVs. The PCM 164, with its onboardpressure sensor 170, watches system line pressure—when the non-leakingtires equalize to the leaking tire, the system pressure does not dropquickly to alert of a leaking tire—the flow rate out of the othernon-leaking tires fills the system line with their pressure, trying toinflate the leaking tire which has a restriction at the WECV 120 thatallows system line pressure to read the higher pressures of thenon-leaking tires. This masks or hides the actual pressure of theleaking tire, and the PCM 164 cannot alert a driver/operator or fleetcommand (through telemetry) that there is a serious tire pressureproblem.

FIG. 15 shows the tire pressure control system of FIG. 14, with a slowleak in one of the tires 150. The present disclosure provides a novelleak detection method for detecting a slow leak in one of the tires 150.This novel leak detection may be described as: “get out and then rampsback in.” In short, the leak detection method of the present disclosurereduces pressure in the common header 104 (i.e. it “gets out” ofpressurizing the common header), and then it slowly ramps pressure backup in the common header 104 (i.e. it “ramps back in”).

If a slow leak is determined by the ECU 180, the ECU 180 may commands afull system exhaust, dropping system pressure in the common header 104to zero, and thereby closing all the WECVs 120. The ECU 180 may thenpulse the intake valve 111, slowly ramping up system pressure in thecommon header 104 while monitoring the system pressure with the pressuresensor 170—this way, the ECU 180 can see at least one of the tires 105(e.g. the left-front (LF) tire) with a low pressure indicative of aleak, and which causes the ramping-up of the system pressure in thecommon header 104 to stall, once the system pressure in the commonheader 104 reaches a pressure equal to the pressure of the left-fronttire.

FIG. 16 shows a first graph 250 of pressure vs time, showing the tirepressures when checking a tire pressure in a system with inflate anddeflate control capabilities. The first graph 250 includes a first plot252 and a second plot 254 showing pressures in “good” or non-leakingtires with an operating pressure of about 100 PSI. The first graph 250also includes a third plot 256 of pressure in a leaking left-front (LF)tire. The first graph 250 also includes a fourth plot 258 of pressure inthe common header 104, as measured by the pressure sensor 170. At timeto, the left-front tire starts to leak. At subsequent time t1 the ECU180 reduces the pressure in the common header 104 to 0 PSI. For example,the ECU 180 may open the exhaust valve 112 and the output control valve113 at time t1. After time t1, the ECU 180 gradually adds air to thecommon header 104 at a relatively low flow rate to gradually increasethe fluid pressure in the common header 104 during a first time period260.

While gradually adding the air to the common header 104, the pressure inthe common header 104 stabilizes at a leak-indicative pressure 264,which is substantially lower than the operating pressure. Thisstabilizing at the leak-indicative pressure 264 is caused by the commonheader 104 reaching the pressure of the left-front tire, causing itsWECV to open, and the gradual adding air to start to pressurize theleft-front tire.

After detecting the leak of one or more tires at the leak-indicativepressure 264, the ECU 180 may proceed to inflate the tires by addingfluid to the common header 104 at an inflation flow rate substantiallyhigher than the first flow rate, as shown by the a third plot 256 ofpressure in the left-front tire increasing during a second time period266. For example, the ECU 180 may command the intake valve 111 and theoutput control valve 113 to a full-open position and/or to a full-openduration in response to determining the leak.

The control solution of the present disclosure may also be used withsystems having only inflate control capability, where the system wecannot “get out” and exhaust system pressure, and where thenormally-closed valves do not equalize to the leaking tire. Inflate onlysystems use normally closed valves, where after an inflation event wecannot “see” the actual tire pressure because the WECV closesimmediately. The system also must be designed to allow system-side leaksdue to rotary union leakage—so after an inflate event, system pressurewill decay which will again mask a leaking tire. Our novel solution isto “ramp-in” and see the leaking tire pressure. See functional plot ofinflate-only below

FIG. 17 shows a second graph 270 of pressure vs time, showing the tirepressures when checking a tire pressure in a system with only inflatecontrol capability. The second graph 270 includes a fifth plot 272 and asixth plot 274 showing pressures in “good” or non-leaking tires with anoperating pressure of about 100 PSI. The first graph 270 also includes aseventh plot 276 of pressure in a leaking left-front (LF) tire. Thesecond graph 270 also includes an eighth plot 278 of pressure in thecommon header 104, as measured by the pressure sensor 170.

The second graph 270 of FIG. 17 is similar to the first graph 250 ofFIG. 16, except the pressure in the common header 104 does not fall allthe way to zero. Instead, the pressure in the common header 104 (asindicated by the eighth plot 278) falls only to an initial pressure p0,at which point the ECU 180 begins the gradual inflation process. Theinitial pressure p0 is shown as being about 50 PSI, although the initialpressure p0 can be any value that is less than a low operating pressureof the tires 150, because the pressure in the in the common header 104is increased from the initial pressure p0 in order to detect a leak.

FIG. 18 shows a flow chart illustrating steps in a first method 300 forcontrolling tire pressure in a system with inflate and deflate controlcapabilities. The first method 300 starts at 302 and proceeds to checksupply and tire pressures at step 304. The supply pressure may bemeasured directly by the pressure sensor 170 in direct fluidcommunication with the common header 104. Methods for checking tirepressures in the tires 150 are discussed further, below.

The first method 300 also determines if a leak is detected at step 306.Methods for detecting leaks in the tires 150 are discussed further,below.

The first method 300 also adjusts frequency of pressure checks at step308 and in response to detecting a leak at step 306. For example, theECU 180 may perform pressure checks on a more frequent basis in responseto detecting a leak. The ECU 180 may be better able to monitor a leak todetermine if a leak is getting worse and in need of attention.

The first method 300 also determines if an inflation event is needed atstep 310. For example, if the ECU 180 detects one or more tires 150 thatwith a pressure below a predetermined low-operating value, the ECU 180may determine that inflation is needed.

The first method 300 also inflates the tires 150 at step 312 and inresponse to determining inflation is needed at step 310. Step 312 mayinclude inflating the tires 150 for a duration of time based on adifference between the pressure in the one or more tires 150 and anoperating pressure value. For example, if the ECU 180 detects one ormore tires 150 that with a pressure below a predetermined low-operatingvalue, the ECU 180 may open the intake valve 111 and the output controlvalve 113 for a duration of time that depends on the amount of inflationrequired.

The first method 300 also determines if a fast leak is detected at step314 and in response to determining inflation is needed at step 310. Forexample, if the ECU 180 detects the system pressure, as measured by thepressure sensor 170, decreasing by a predetermined amount over a givenperiod of time, the ECU 180 may signal a fast leak as being detected.The first method 300 may return to step 304 in response to detecting nofast leak at step 314.

The first method 300 also signals a fast leak at step 316 and inresponse to detecting a fast leak at step 314. For example, the ECU 180may light a diagnostic lamp, set a diagnostic trouble code (DTC), and/orcommunicate a message to a remote receiver indicating the detection ofthe fast leak.

The first method 300 also isolates the tires at step 318 and in responseto detecting a fast leak at step 314. For example, the wheel end checkvalves 120 may be closed to prevent air from flowing out of thenon-leaking tires 150 into the common header 104 and out of a leak.

The first method 300 also determines if a deflation event is needed atstep 320. For example, if the ECU 180 detects one or more tires 150 thatwith a pressure above a predetermined high-operating value, the ECU 180may determine that deflation is needed.

The first method 300 also deflates one or more of the tires 150 at step322 and in response to determining deflation is needed at step 320. Step322 may include deflating the tires 150 for a duration of time based ona difference between the pressure in the one or more tires 150 and anoperating pressure value. For example, if the ECU 180 detects one ormore tires 150 that with a pressure above a predetermined high-operatingvalue, the ECU 180 may open the exhaust valve 112 and the output controlvalve 113 for a duration of time that depends on the amount of deflationrequired. The first method 300 may return to step 304 after deflatingthe tires 150 at step 322.

The first method 300 also includes idling at step 324 and in response todetermining that deflation is not needed at step 320. This step 320 mayprovide a periodic basis for the first method 300.

FIG. 19 shows a flow chart illustrating steps in a second method 350 forcontrolling tire pressure in a system with only inflate controlcapability.

The second method 350 starts at 352 and proceeds to check supply andtire pressures at step 354. The supply pressure may be measured directlyby the pressure sensor 170 in direct fluid communication with the commonheader 104. Methods for checking tire pressures in the tires 150 arediscussed further, below.

The second method 350 also determines if the air supply is good at step356. For example, the ECU 180 may measure the pressure of an air supply.Alternatively or additionally, step 358 may include receiving a signalfrom a supply system, such as a controller on a compressor used as anair supply to the system.

The second method 350 also determines if a leak is detected at step 58.Methods for detecting leaks in the tires 150 are discussed further,below.

The second method 350 also adjusts frequency of pressure checks at step360 and in response to detecting a leak at step 358. For example, theECU 180 may perform pressure checks on a more frequent basis in responseto detecting a leak. The ECU 180 may be better able to monitor a leak todetermine if a leak is getting worse and in need of attention.

The second method 350 also determines if an inflation event is needed atstep 362. For example, if the ECU 180 detects one or more tires 150 thatwith a pressure below a predetermined low-operating value, the ECU 180may determine that inflation is needed.

The second method 350 also inflates the tires 150 at step 364 and inresponse to determining inflation is needed at step 362. Step 364 mayinclude inflating the tires 150 for a duration of time based on adifference between the pressure in the one or more tires 150 and anoperating pressure value. For example, if the ECU 180 detects one ormore tires 150 that with a pressure below a predetermined low-operatingvalue, the ECU 180 may open the intake valve 111 and the output controlvalve 113 for a duration of time that depends on the amount of inflationrequired.

The second method 350 also determines if a fast leak is detected at step366 and in response to determining inflation is needed at step 310. Forexample, if the ECU 180 detects the system pressure, as measured by thepressure sensor 170, decreasing by a predetermined amount over a givenperiod of time, the ECU 180 may signal a fast leak as being detected.second method 350 may return to step 354 in response to detecting nofast leak at step 366.

The second method 350 also signals a fast leak at step 368 and inresponse to detecting a fast leak at step 366. For example, the ECU 180may light a diagnostic lamp, set a diagnostic trouble code (DTC), and/orcommunicate a message to a remote receiver indicating the detection ofthe fast leak.

The second method 350 also includes idling at step 370 and in responseto determining that deflation is not needed at step 362. This step 370may provide a periodic basis for the second method 350. Step 370 mayalso be performed in response to determining that the supply is not goodat step 356. In this way, the second method 350 may wait andperiodically check for the supply to return to a “good” or functionalstate before performing other tasks, such as checking for leaks, andinflating, if necessary.

FIG. 20 shows a flow chart illustrating steps in a third method 400 forchecking a tire pressure. The third method 400 may be used, for example,to determine if a leak is detected in any of the tires 150 at step 306or at step 358.

The third method 400 starts at step 402 and proceeds to pulse air into atire control line until pressure peaks at step 404. Step 404 mayinclude, for example, the ECU 180 commanding the intake valve 111 andthe output control valve 113 to be open to supply pressurized air fromthe air source 130 to the common header 104, until the pressure in thecommon header 104, as measured by the pressure sensor 170, stabilizes ata particular value (i.e. the peak pressure).

The third method 400 also includes recording the peak pressure as thesupply pressure at step 406. For example, the ECU 180 may record thepeak pressure resulting from step 404 as representing the supplypressure.

The third method 400 also includes pulsing a small amount of air intothe tire supply line at step 408. Step 408 may include, for example, theECU 180 commanding the intake valve 111 and the output control valve 113to be open for one or more durations to supply pressurized air from theair source 130 to the common header 104.

The third method 400 also includes determining, after step 408, if thepressure in the tire supply line (e.g. the common header 104) settlesbelow the peak pressure at step 410. If the pressure does not settle ata pressure below the peak pressure, the third method 400 may return backto step 408 and continue to pulsing another small amount of air into thetire supply line.

The third method 400 also includes recording a pressure below the peakpressure as a low-tire pressure at step 412 and in response todetermining that the pressure in the tire supply line having settledbelow the peak pressure at step 410. The third method 400 may continueout of the pressure check loop at step 414 and after step 414.

FIG. 21 shows a flow chart illustrating steps in a fifth method 500 fordetecting a leak in a pressure vessel of a system including a pluralityof pressure vessels in fluid communication with a common header. In someembodiments, the pressure vessels may include tires installed on avehicle. However, the fifth method 500 may be used with other types ofpressure vessels, such as tanks in a tank farm.

In some embodiments, the common header is in fluid communication witheach of the tires via a wheel-end check valve configured to allow fluidflow from the common header to a corresponding one of the tires whileblocking fluid flow in an opposite direction.

The fifth method 500 includes reducing a fluid pressure in the commonheader to a first predetermined value at step 502. The firstpredetermined value may be a pressure value below an operating pressureof the plurality of pressure vessels. In some embodiments, the firstpredetermined value may be equal to or approximately equal to an ambientair pressure.

In some embodiments, step 502 may include opening an exhaust valve torelease fluid from the common header. For example, in an inflate/deflatetype system, the ECU 180 may command the exhaust valve 112 to releaseair from the common header 104. Alternatively, step 502 may includefluid leaking from the common header with no controlled valves in fluidcommunication with the common header being commanded open. For example,in an inflate-only type system, the ECU may wait and monitor thepressure in the common header 104 as fluid leaks therefrom. For example,air may leak out of the common header 104 from one or more rotary unionsthat couple the common header 104 to the tires 150.

The fifth method 500 also includes gradually adding fluid to the commonheader at a first flow rate at step 504 to increase the fluid pressurein the common header from the first predetermined value.

In some embodiments, steps 502 and 504 are each performed on a periodicbasis. For example, the ECU 180 may perform at least steps 502 and 504of the fifth method 500 in order to check for leaks on a regular basis,such as daily, weekly, etc.

The fifth method 500 also includes monitoring, after gradually addingthe fluid to the common header, the fluid pressure in the common headerat step 506.

In some embodiments, step 506 includes opening a proportional valve toan intermediate position to allow flow from an air source to the commonheader. Alternatively or additionally, step 506 may include opening anon-proportional valve for a duty cycle duration in each of a pluralityof time periods to allow flow from an air source to the common header.

The fifth method 500 also includes determining a leak in at least onepressure vessel of the plurality of pressure vessels at step 508, basedon the fluid pressure in the common header after gradually adding thefluid to the common header. In some embodiments, step 508 includesdetermining the fluid pressure in the common header settling at a valuebelow the operating pressure of the plurality of pressure vessels.

The fifth method 500 also includes inflating the at least one pressurevessel by adding fluid to the common header at an inflation flow ratesubstantially higher than the first flow rate at step 510 and inresponse to determining the leak in the at least one pressure vessel.For example, the ECU 180 may command the intake valve 111 and the outputcontrol valve 113 to a full-open position and/or to a full-open durationin response to determining the leak at step 508.

The fifth method 500 also includes activating a diagnostic indicator atstep 512 and in response to determining the leak in the at least onepressure vessel at step 508. For example, the ECU 180 may cause anindicator light to be illuminated and/or for a message to be displayedon a display screen, indicating the detected leak.

The fifth method 500 also includes setting a diagnostic trouble code atstep 514 and in response to determining the leak in the at least onepressure vessel. For example, the ECU 180 may set a trouble code inmemory that can be subsequently read to indicate the detection of theleak.

The fifth method 500 also includes transmitting a message to remotereceiver at step 516 and in response to determining the leak in the atleast one pressure vessel. For example, the ECU 180 may cause a messageto be transmitted to a fleet management system. Such a message may betransmitted via a digital communications network, such as a cellulardata network and/or via the internet.

The system, methods and/or processes described above, and steps thereof,may be realized in hardware, software or any combination of hardware andsoftware suitable for a particular application. The hardware may includea general purpose computer and/or dedicated computing device or specificcomputing device or particular aspect or component of a specificcomputing device. The processes may be realized in one or moremicroprocessors, microcontrollers, embedded microcontrollers,programmable digital signal processors or other programmable device,along with internal and/or external memory. The processes may also, oralternatively, be embodied in an application specific integratedcircuit, a programmable gate array, programmable array logic, or anyother device or combination of devices that may be configured to processelectronic signals. It will further be appreciated that one or more ofthe processes may be realized as a computer executable code capable ofbeing executed on a machine readable medium.

The computer executable code may be created using a structuredprogramming language such as C, an object oriented programming languagesuch as C++, or any other high-level or low-level programming language(including assembly languages, hardware description languages, anddatabase programming languages and technologies) that may be stored,compiled or interpreted to run on one of the above devices as well asheterogeneous combinations of processors processor architectures, orcombinations of different hardware and software, or any other machinecapable of executing program instructions.

Thus, in one aspect, each method described above and combinationsthereof may be embodied in computer executable code that, when executingon one or more computing devices performs the steps thereof. In anotheraspect, the methods may be embodied in systems that perform the stepsthereof, and may be distributed across devices in a number of ways, orall of the functionality may be integrated into a dedicated, standalonedevice or other hardware. In another aspect, the means for performingthe steps associated with the processes described above may include anyof the hardware and/or software described above. All such permutationsand combinations are intended to fall within the scope of the presentdisclosure.

The foregoing description is not intended to be exhaustive or to limitthe disclosure. Individual elements or features of a particularembodiment are generally not limited to that particular embodiment, but,where applicable, are interchangeable and can be used in a selectedembodiment, even if not specifically shown or described. The same mayalso be varied in many ways. Such variations are not to be regarded as adeparture from the disclosure, and all such modifications are intendedto be included within the scope of the disclosure.

Although omitted for conciseness, the preferred embodiments includeevery combination and permutation of the various system components andthe various method processes, wherein the method processes can beperformed in any suitable order, sequentially or concurrently.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the preferred embodiments of the invention withoutdeparting from the scope of this invention defined in the followingclaims.

What is claimed is:
 1. A method for detecting a leak in a pressurevessel of a system including a plurality of pressure vessels in fluidcommunication with a common header, said method comprising: reducing afluid pressure in the common header to a first predetermined value belowan operating pressure of the plurality of pressure vessels; graduallyadding fluid to the common header at a first flow rate to increase thefluid pressure in the common header from the first predetermined value;monitoring, after gradually adding the fluid to the common header, thefluid pressure in the common header; and determining, based on the fluidpressure in the common header after gradually adding the fluid to thecommon header, a leak in at least one pressure vessel of the pluralityof pressure vessels.
 2. The method of claim 1, wherein the plurality ofpressure vessels include tires installed on a vehicle.
 3. The method ofclaim 1, wherein the common header is in fluid communication with eachof the plurality of pressure vessels via a wheel-end check valveconfigured to allow fluid flow from the common header to a correspondingone of the plurality of pressure vessels while blocking fluid flow in anopposite direction.
 4. The method of claim 1, wherein determining theleak in the at least one pressure vessel includes determining the fluidpressure in the common header settling at a value below the operatingpressure of the plurality of pressure vessels.
 5. The method of claim 1,wherein reducing the fluid pressure in the common header and graduallyadding the fluid to the common header are each performed on a periodicbasis.
 6. The method of claim 1, wherein reducing the fluid pressure inthe common header includes opening an exhaust valve to release fluidfrom the common header.
 7. The method of claim 1, wherein reducing thefluid pressure in the common header includes fluid leaking from thecommon header with no controlled valves in fluid communication with thecommon header being commanded open.
 8. The method of claim 1, whereingradually adding fluid to the common header includes opening aproportional valve to an intermediate position to allow flow from an airsource to the common header.
 9. The method of claim 1, wherein graduallyadding fluid to the common header includes opening a non-proportionalvalve for a duty cycle duration in each of a plurality of time periodsto allow flow from an air source to the common header.
 10. The method ofclaim 1, further comprising: inflating the at least one pressure vesselin response to determining the leak in the at least one pressure vesselby adding fluid to the common header at an inflation flow ratesubstantially higher than the first flow rate.
 11. The method of claim1, further comprising: activating a diagnostic indicator in response todetermining the leak in the at least one pressure vessel.
 12. The methodof claim 1, further comprising: setting a diagnostic trouble code inresponse to determining the leak in the at least one pressure vessel.13. The method of claim 1, further comprising: transmitting a message toremote receiver in response to determining the leak in the at least onepressure vessel.
 14. A system for managing pressure in a plurality oftires of a vehicle, comprising: a manifold defining a channel andconfigured to distribute compressed air from a compressed air source; acommon header providing fluid communication between the manifold andeach of the plurality of tires; a control valve configured to controlair flow from the compressed air source to the common header; a pressuresensor configured to monitor a pressure in the common header; and anelectronic control unit in functional communication with the controlvalve and the pressure sensor, the electronic control unit configuredto: reduce a fluid pressure in the common header to a firstpredetermined value below an operating pressure of the plurality oftires; gradually add air to the common header to increase the fluidpressure in the common header from the first predetermined value;monitor, after gradually adding the fluid to the common header, thefluid pressure in the common header; and determine, based on the fluidpressure in the common header after gradually adding the air to thecommon header, a leak in at least one of the plurality of tires.
 15. Thesystem of claim 14, wherein the common header is in fluid communicationwith each of the plurality of tires via a wheel-end check valveconfigured to allow fluid flow from the common header to a correspondingone of the tires while blocking fluid flow in an opposite direction. 16.The system of claim 14, wherein determining the leak in the at least oneof the plurality of tires includes electronic control unit determiningthe fluid pressure in the common header settling at a value below theoperating pressure of the tires.
 17. The system of claim 14, wherein theelectronic control unit is configured to reduce the fluid pressure inthe common header and to gradually add the fluid to the common header ona periodic basis.
 18. The system of claim 14, further comprising anexhaust valve configured to control air flow from the channel to anexhaust port, and wherein reducing the fluid pressure in the commonheader includes the electronic control commanding the exhaust valve toopen.
 19. The system of claim 14, wherein gradually adding fluid to thecommon header includes opening a proportional valve to an intermediateposition to allow flow from the compressed air source to the commonheader.
 20. The system of claim 14, wherein gradually adding fluid tothe common header includes opening a non-proportional valve for a dutycycle duration in each of a plurality of time periods to allow flow fromthe compressed air source to the common header.